Fluid pressure brake apparatus



16, 1957 5 COOK FLUID PRESSURE BRAKE APPARATUS Filed NOV. 17, 1953 N VN mm. mm fin. 00

INVENTOR. Earle S. CooK AT TOQNEY FLUID PRESSURE B APPARATUS Earle S. Cook, Pittsburgh, Pa., assignor to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application November 17, 1953, Serial No. 392,649

4 Claims. (Cl. 303-60) This invention relates to fluid pressure brake apparatus and more particularly to the graduated control type adapted for use on trains in European service, in which the degree of brake application and brake release is controlled according to the extent of reduction and restoration in pressure of fluid in a brake pipe relative to that in a control reservoir.

In the copending application of Glenn T. McClure, Serial No. 388,189, filed October 26, 1953, there is shown and described an apparatus of the above type comprising, on each brake-equipped car, a charging valve device operative upon initiation of a brake application on such car to cut off fluid pressure communication be tween the brake pipe, the control reservoir and an auxiliary reservoir, and operative when such application has been released, to locally connect a single brake pipe passage to both the control and auxiliary reservoirs so that control reservoir pressure may equalize with brake pipe pressure and the auxiliary reservoir may be recharged to brake pipe pressure, respectively, within the usual prescribed period of time.

As will be noted from a study of the aforementioned application, at the time the charging valve device moves to charging position after final release of a brake application on the car, auxiliary reservoir pressure will, by virtue of the operation of a charging check valve device, be about one and seven-tenths p. s. i. less than the pressure of fluid in a certain chamber in a service valve device by way of which said reservoir is initially recharged from the brake pipe, although fluid pressure in said chamber may not be as high as brake pipe pressure, for reasons to be explained subsequently; and control reservoir pressure will at such time be about three p. s. i. higher than the pressure of fluid in said certain chamber; in other words, control reservoir pressure will be about four and seven-tenths p. s. i. more than auxiliary reservoir pressure. Thus, when the charging valve device moves to charging position, fluid under pressure will flow initially from the control reservoir to the auxiliary reservoir; and since the volume of the auxiliary reservoir is much greater than that of the control reservoir, an undesirable, rapid depletion of control reservoir pressure will temporarily occur which latter pressure will not be fully restored until both the auxiliary and control reservoirs have been recharged by way of the brake pipe to normal operating brake pipe pressure. If a reapplication of the brakes is initiated before control reservoir pressure has been fully restored, the charging valve device, by moving to cut-ofi position, will bottle up fluid in the control reservoir at a pressure less than proper datum value, with the result that attainable brake cylinder pressure will be reduced by about two and one-half p. s. i. for every p. s. i. the control reservoir pressure is below such proper value.

It will therefore be observed that if the brakes are reapplied at such frequent intervals that control reservoir pressure successively depletes into auxiliary reservoir and cannot be fully restored during full release of brakes asst between reapplications, such as may occur when the train is descending a long grade, there is a possibility that the attainable brake cylinder pressure may become so reduced as to render train operation hazardous.

It is therefore the principal object of this invenion to provide an improved apparatus of the above type for substantially eliminating the difliculty just described.

According to this object, novel means are provided whereby the control and auxiliary reservoirs are opened, after final release of the brake application, to separate brake pipe passages which are isolated from each other by choke means so that control reservoir pressure will equalize at a controlled rate into the brake pipe, rather than into the auxiliary reservoir as heretofore; and since the volume of the brake pipe on the car is less than that of the control reservoir and is very small compared to that of the auxiliary reservoir, and since brake pipe pressure will not only be higher than auxiliary reservoir pressure at the time of such opening but will be within several p. s. i. of control reservoir pressure, the latter pressure will not be reduced substantially despite very frequent reapplications of the brakes.

Other objects and advantages will become apparent from the following, more detailed description of the invention and from the accompanying drawing, wherein the single figure is a diagrammatic view of that portion of a brake apparatus embodying the invention.

Description Since the novel structure is adapted for use with fluid pressure brake apparatus which may, for sake of illustration, be of the type shown and described in the aforementioned copending application, the disclosure in the accompanying drawing and in the following description has been limited to only such structure as is essential to a clear understanding of the invention; and the reader is referreed to said application for a more detailed explanation of components not fully described herein.

Referring to the drawing, the brake apparatus comprises the usual brake pipe 1 which is adapted to extend through the train and to be charged with fluid at a pressure controlled in the well-known manner by manual operation of the usual engineers automatic brake valve device (not shown) on the locomotive, for thereby controlling application and release of the brakes on the connected cars of the train.

On each brake-equipped car of the train there is provided a brake controlling valve device 2 adapted to respond to a reduction in pressure of fluid in the brake pipe 1 relative to the pressure in a control reservoir 6 for supplying fluid under pressure from the usual auxiliary reservoir 3 to the usual brake cylinder device 4 for efliecting a corresponding degree of brake application on such car; said valve device being adapted to respond to an increase in brake pipe pressure relative to control reservoir pressure to efiect a corresponding release of fluid under pressure from said brake cylinder device to atmosphere, as well as perform other functions only some of .which are directly pertinent to the invention and will hereinafter be described. a

The brake controlling valve device 2 comprises a combination pipe bracket and casing, designated generally by the reference numeral 5, and consisting of a pipe bracket 5a and a casing 5b; to this bracket the brake pipe 1, auxiliary reservoir 3, brake cylinder device 4 and the control reservoir 6 are adapted to be connected. The brake controlling valve device 2 also comprises the usual graduated control portion or service valve device 7 and the usualcharging check valve device 8, both of which devices may be identical in structure and operation with those shown and described in the aforementioned application.

According -to the invention,the brake controlling valve 7 .device 2 also comprises I a charging valve-device 9, .a

a and -valve .-:16- -which l extends through the non-pressure chamber 14'and-has slidable,"--sea1ing--engagement with :the wall (of acoaxial'ly aligned bore 117- in casing er chamberllris adapted to-bebharged=with fluid qin'der presslure or vented to atmosphere the usual manner 'by-\vay-'of a= passage 18in the casing. -When chamber 13-is dev :+id of fluid under pressure, a spring 19; isidisposed inchamber 1 4 -a-ndac't-ing on the-diaphra'gm fol-lower 15- is adapted-to urge the diaphragm ll -and valve ifi into oneposit-ion, hereinafter referred toas the charging positionof thecharging valve device a 9. When, on theother -hand-,'fiuid under pressure is sup- --deflect=againstresistance-yof-spring"19 and-thereby advance theavalve 15 to 'another position, hereinafter referred 5.10 as the -cut=ofi-position of charging -valve tween-apassageZl 'and'a'passage22g and at the same time, theprojecting end of said stem is adapted to uncovera passage "2310a chamber-24' definedlby' the proiecting'end of said stern and the base-and wall of bore 17. 'Thepassage -21'isconstantly'open,to'the brake pipe 7 '1- by Way'of a choke 25, a chamber26, a'choke'27 and a brakepipe 'passage-'28,'for reasons to be explained subsequently; said chokes being 'mounted infthe bracket "5a. "Thei'p'assage '22 is constantly open to the, control reservoir 6;anda branch of sa'idpassage is. also constantly open tothe'usual contrbl cjharnber' 2910f the service 'valve' device 7, so' that; pressures, of Qfluid ,in the brake pipeliand in 's'aidichamber and control reservoir "'may"'equ alize when'the charging .v'alve device 9 .is in charging position. The passagefziLisponstantly. open tothe brake pipe liby way of afch'okef3flin the bracket a and the 'chamberzlfi,.choke. 27..and,brake .pipespassage 28. Thechamber"241is opento the auxiliaryres- 'ervoir3 by wayhofaw passage 31 and the usualncommw nication, including aiichamberi32 encirclingstheuservice valve device7,-and lthetiusualipassage r33, choke. 34, passage35, .b'rake cylinder'limiting valve device (not-shown) and passage-36.

' It will'be'noted 'that the, choke,.27 .is in series with 'thech'ok'es25, T30, the two. latter chokes being in. parallel'with each other. iThesize of choke25 in conjunction with that 'of jchoke 27,, v is such that. charging of ,the control reservoir :6 Willgduring initial chargingwof the equipment, he accomplishedby way,.of brake pipepassage Z8W'ithin a pres'ci'ibed time; .andithe size of-choke 39' in fc'onjunction .with that of .choke 2743: such: vthat chargingjof'thel auziiliary reservoir will,r-during1such initial fchar'ging,'j'bellikewise accomplished;from passage 23) within the" isamel time, ,.'since previously noted, rthe volume of control reservoir 6. is ,shbstantially smaller than 'Lth'at' .of theja'uziiliary rreservoiri i'i. {It follows, therefore, "that jthe combined Qflow capacity =rof the '1 control reservoir "charging chokes; 2,7, 25 =iS ICSS EthEH hatof the'auxiliary rese-rvoir;charging.chokes 27; 3} andyhence. thatchoke"25 is of smaller size than-.chokevSO. ,.-The

choke 27 is provided so that the chokes 25, 30 may be larger in- -size, I asa--precaution--againstclogging,=than could otherwise be obtained by use of charging chokes 25, 39 along for the respective prescribed flow capacities. The flow capacity of choke 34 is large compared to that of the series connected chokes 27, 30 and hence does not efiect a further reduction in the rate of charging of the auxiliary reservoir 3; said choke 34 being provided for controlling'the rate-of-flow of fluid under pressure from, said,auxiliary reservoirtto the brakecylinder device 4, as in-:the. -afore mentioned application.

When the charging valve device 9 is ;-in;,cut+ofinposition, the combination stem and valve 16 is adapted to be "so disposed as -to-elose-oif communication of passages 21, 22 with eachother by.:way;of cavity 20, for thereby causing fluid under pressure to be bottled up in the passage 22, control reservoirfi and control chamber 29 of service valve device 7, for reasons to be ex- -plained -.subsequently;z and=also in suchcut otfposition, ithe projecting end of said combination stem and valve is adapted: to sealoft-passage 23 fron'i-charnber'124 so a as to close. 01f. communication between-thebrake pipe 1 1 andtauxiliary reservoir 3, forreasons also-to be explained subsequently.

The control reservoir overcharge check valve device 1%). comprises avalve '37, which. may be disc 'shaped: and

scalable against a projecting,-annular seat rib'element -38. umounted in casing 55. The'valve 37'issubject'at one'sidetopresstue of fiuidin achamber 39, which is defined by the =inner-wall-of the annular rib' element 38 and'econstantly open to a' branch of'the passagef 21; and "subject atits opposite side to pressure of fluid in a chamberi4ii-which -is constantly opento a' passage lthat is open througha choke 42 tot-he brake-pipe, -passage28.

-During control reservoir overcharge .dissipation, the flow capacity of choke -42'supplements thatof 'the cornbined 'fiow capacityof ehokes25,27, so that such dissipation may-beat a rate morerapid'than that obtainedlduring initial charging by the chokes'27, 25 alone, yetvnot so rapid as might'prevent a brake application or prevent operation of theapparatusinthe manner hereafter to be described.

The auxiliary reservoir overcharge check valve deyice 11 comprises a valve 43 which may be disc-shaped and seatable against a projecting annular seat rib -elemenL44 mounted inocasingdb. The valve43, issirbjectat one .side i to pressure of fluid .in a chamber 45 'definedby the inner wall of the annular rib "element 44 andhconstantlyoscpen toa'branchoffithe passage" 23; and subject at, its opposite side topressure offiuid in'a 'chamberd. that is constantly open to a passaged? which, in turn, is open through a choke t8 tothe brake pipe passage. 28.

During. auxiliary reservoir overcharge "dissipation, the flow capacity of choke 48. supplements tint of thc combined'fiow capacity of the series-arranged chokes; 3t), 27, so that such'dissipation may be aria rate more rapid than that obtained and permitted. during initialcharging by the chokesi'27, ,Zatl alone, yet notso. rapid asmight prevent a brakeapplicationor. preventioperationof the apparatus in the manner hereafterto-be described.

it is to be notedtthat thechoke 48 is'of smaller flow capacity than that of choke 42.

The improved brake apparatusalso comprisesytheusual manually adjustable. service selector valve gdevieeai a quick service valve device 5% and an inshotvalve device 51, all of which may be identical withflrose, 'shownand described in the aforementioned copendingapplication.

The quick service .valve device 59 compjrises,..briefiy, a flexible diaphragm"57 which is operatively connected throriglvthe medium ofaodiaphragm follower to a rod 58 that has sealing, slidably'guided engagement .withthe wall of a-bore-inthe-casing. The diaphragm57 isosubfeet at one-'sideto pressure of fluid-in a chamber 59 that isiiopeni to a-v-branch ofpassage fi and is 'subject atjthe opposite side to; pressure of fluid in a "chamber 66 that is 9 be disconnected from the brake pipe passage 28 in consequence of the earlier deflection of the quick service valve diaphragm 57 to its normal position due to increased brake pipe pressure in chamber 60 and action of spring 61.

After the brakes fully release, there will be the usual short interval of time during which fluid pressure will blow down to atmosphere at a controlled rate from chamber 13 of charging valve device 9 by way of passage 18, the choke 99, passage 83, and cavity 93 of the service valve device 7; and during this same time interval brake pipe pressure and hence the pressure of fluid in passage 28 and the passages 21 and 23 will increase toward normal operating value. Hence, when the charging valve device 9 moves to charging position under action of spring 19 at the expiry of this time interval, brake pipe pressure in passage 21 will always be within several p. s. i. of control reservoir pressure and may even equal the latter pressure; whereas auxiliary reservoir pressure will be about one and seven-tenths p. s. i. below that of the bottled-up fluid in chamber 52 of the service valve device 7, or in other words, it may be as much as about four and seven-tenths p. s. i. below brake pipe pressure in passage 28, if the latter pressure is then up to normal operating value.

In this improved apparatus, when the charging valve device 9 moves to charging position, fluid under pressure will flow from the brake pipe passage 28 by way of previously described communication including passage 23 and chamber 24 to the auxiliary reservoir 3; and if, at such time, the pressure of fluid in brake pipe passage 28 and hence in passage 21 is less than that in the control reservoir 6, control reservoir pressure will equalize into the brake pipe 1 at a rate controlled by the combined effects of the series connected chokes 25, 27 and the control reservoir overcharge dissipation choke 42, but no depletion of control reservoir pressure into the auxiliary reservoir will occur due to the pressure head in the brake pipe 1 and hence in chamber 26 and the fact that the control reservoir 6 is isolated from the auxiliary reservoir 3 by way of chokes 25, 30. It is to be noted, however, that before any appreciable depletion of control reservoir pressure into the brake pipe occurs, the pressure of fluid in said brake pipe and hence in passage 28 will have built up to normal operating value, successively terminating further depletion and then, with overcharge check valve 37 closed, restoring control reservoir pressure by way of chokes 27, 25 and passage 21; whereas the auxiliary reservoir may not, at the time of surh restoration of pressure, have been fully recharged due to the relatively large volume of the latter reservoir and the initially greater differential between auxiliary reservoir and brake pipe pressure.

It will now be noted that control reservoir pressure, if reduced at all, will not reduce appreciably following a brake release; and that even it frequent reapplications of the brakes are made while descending a long grade, the control reservoir pressure will never be materially depleted.

Overcharge dissipation Assume now that the pressure of fluid in the control and auxiliary reservoirs exceeds that in the brake pipe, due for example to a changeover from a locomotive wherein the usual feed valve device had been set somewhat higher than that in the substituted locomotive, with the result that brake pipe pressure is reduced several p. s. i. when such changeover is completed; and that, in accordance with the usual practice, the handle of the aforementioned brake valve device on the substituted locomotive is in running position at the time the brake pipe on the locomotive is opened to that on the cars of the train.

Under such condition, with the brakes released on the cars, the charging valve device 9 will be in charging position. Since brake pipe pressure is now lower than heretofore, fluid under pressure will flow from the overcharged control reservoir 6 and control chamber 29 of service valve device 7 by way of passage 22 to passage 21, whence it will flow not only by way of chokes 25, 27 to brake pipe passage 28 but also by way of chamber 39 and past the unseated check valve 37 of the overcharge check valve device 10 to chamber 40 and thence via passage 41 and choke 42 to the brake pipe passage 28, for dissipating such overcharge to the brake pipe 1; the pressure in said brake pipe being then maintained at selected pres sure by well-known operation of the brake valve device.

Similarly, fluid under pressure will flow from the over charged auxiliary reservoir 3 by way of chamber 24 and passage 23 whence it will flow not only via chokes 30, 27 to the brake pipe passage 28 but also via chamber 45 and past the unseated check valve 43 of overcharge check valve device 11 to chamber 46 and thence via passage 47 and choke 48 to said brake pipe passage 28, for dissipating such overcharge to the brake pipe 1.

It should be noted that all of the chokes heretofore described, except the choke 99, are disposed in the pipe bracket 5a for thereby permitting easy access thereto and permitting convenient modification of choke sizes according to intended conditions of service.

Summary It will now be seen that the improved fluid pressure brake apparatus embodies a novel arrangement for preventing depletion of control reservoir pressure into the auxiliary reservoir following the release of a brake application, with the result that the possibility of an appreciable reduction in control reservoir pressure is prevented even when the brakes are reapplied at frequent intervals, such as while descending a long grade.

It will also be seen that the dissipation of any excessive pressure in the control and auxiliary reservoirs is accomplished by separate overcharge check valve devices for each such reservoir.

Having now described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a fluid pressure brake apparatus of the type comprising a valve device responsive to a reduction in pressure of fluid in a brake pipe relative to that in a control reservoir for supplying fluid under pressure from an auxiliary reservoir to a brake controlling communication for efiecting an application of brakes and responsive to restoration of brake pipe pressure toward equality with control reservoir pressure for efiecting a release of brakes, the combination of a first passage constantly open to said brake pipe, a second passage constantly open to said brake pipe, charging valve means responsive to release of fluid under pressure from a chamber to open said first passage to said auxiliary reservoir and also open said second passage to said control reservoir and operative upon supply of fluid under pressure to said chamber to close ofi said first passage and second passage from said auxiliary reservoir and control reservoir, respectively, first choke means interposed in said first passage for controlling, at one rate, flow of fluid under pressure from said brake pipe to said auxiliary reservoir, second choke means interposed in said second passage for controlling flow of fluid under pressure between said brake pipe and control reservoir at another rate, a passageway through which fluid under pressure may be conveyed to and released from said chamber, another valve device responsive to a reduction in brake pipe pressure for supplying fluid under pressure to said chamber via said passageway, and third choke means interposed between said chamber and said brake controlling communication for restricting flow of fluid under pressure therebetween.

2. In a fluid pressure brake apparatus, in combination, a brake pipe, a control reservoir, an auxiliary reservoir, a brake controlling communication to which fluid under pressure is supplied for eifecting an application of brakes '1 1 and from which fluidrundei pressureis released for efiect- "ing a release I of brakes, "a fitst communicationthrough Jvhich fluid unrlelr pressure may "flow from"-saidbrake pipe to said'auxiliary reservoir, 21 second communication *through-which fluid under pressure" may flow 'fronr-said i a'ValVe'deViceiQrsnpplying fluid 'underpressure from said brake pipeto'said volume 'followinga reduction in brake ipe *pressure'and for termina'ting' such supply 'upon' a rest-erationof'=brake pipe pressure,anothervalve 'device for closing said "volume to'said' chamber pun'tihpressure in said' braiiecontrollingcommunication is reducedibelow ars'eleetedvalue and then opening said volume' to said chairmen-and third choke'means'interposed"between -said chamber and brakecontrollingcommunication for restric- 'ting the rate of blowdown"offluidunderpressurefrom said chamber to the latteraacommunication for thereby deferring operation of said charging valve means to reopensaid-first andsecond communications.

3. lu a fluid pressure brake apparatus of'the type comprising a-valvedevice-responsiveto 'a reduction in pressure of fluid "in abrakepipe relative to that in. acontrol reservoir 'for supplying fluidmnder pressure from an auxiliary reservoir "to a. brake controlling communication for efi ec'ting' an .apPlication "of brakes and responsive to restoration ofbrakepipe pressure toward. equality with control reservoirpressure'for effecting a release 'of'brakes, the combination of a first passagetopen to said brake-pipe, a second passage open to said. brake pipe, charging valve means responsive to release of fluid under pressure from'a chamber to' assume a charging position in which said first passage isopen to said auxiliary reservoir'and said second passage is open toisaid control reservoirand-operative upon supply'of fiuidiunder pressure-to said" chamber-to" assume a cut-offposition in which said first "passage and second passage are closed to saidaturihaiyreservoir and 'control'reservoir, respectively, first=- choke means interposed"between 'said' brake pipe and "first passagefor controlling at: one 'rate, fiow of fluid 'under *pressure "from said"- brake 1: pipe 'to said auxiliary reservoir; second-choke means "interposed between said brake pipe and second passage for controlling, at another rate; flow of fluid under pressurefrom said brakepipeto said control reservoir, 21" first restricted. communication open to said brake; pipe, auxiliary reservoir overchage 'checlc'valve'means"subject opposingly to fiuid'pressures'in said firstrestricted communication and said first passage for permitting flow of fluid under pressure only from "the. latter to theformer by way or a branch of' saidfirst, passage when, with said. charging valve means in its.said charging position,ffluid.pressure -12 hr'Said auxiliaryreservoir exceeds that in said brake pipe -and=-whereby such excessive auxiliary reservoir pressure is dissipated at--a=:rate-'corresponding to-"the combined fl ow'capacit-ies of said' firstrestricted communication and said first choke means, a second restrictedconnnunication open to said brake pipe, and control reservoir oven charge'che'ek valve means subject opposinglyto fluid-pressures insaid'second restricted communication and in said second;passage for permitting "flow of fluid under pressure-only from the latter to the-formerby-Way'of a branch of-said second passage-WhenyWithsaid charging valve means in its said"charging-position, fluid-pressure in said control reservoir exceeds that in said brake pipe and whereby --such excessive control reservoir pressure capacities .of said second restricted communication a and 's'aid second choke means. 7

-43 Ina fluid=pressurebrake= apparatus ofthe type comprising aserV-ice valve d'e'vice responsive to a reduction in pressure erfluid in -a brake pipe "relative to a" datum pressure in a control-reservoir to supply fluid under pressure froman auuiliary-reservoir via a brake controlling communication to a 'brake applyingmeans for eifecting anapplication of br'akes, the-cornhinationof a pipe bracket to which are connected said brakepipe, brake .iapplying m ans, F control reservoir, and auXiliary reservoir; acasing onwhicl'r said pipe bracket is mounted,'--,a char'ging valvezdevice -inzpart defined'by said casing and comprising a movable abutment subject opposingly to pressure of' flu'id in a controlchamber audaction of 1 a bias: spring and: further comprising valve means carried by said movable abutment, a first' passage in said casingand open -to said-brake pipe, :first choke means mounted :in saidpipe bracket for restrictingfiow of fluid underpressurefihrough saidfirst passage, a sec ond: :passage' in said: casing and open to said brake pipe, secondic-h'okewmeans mounted in said pipe bracket for restricting flow' of fluidunder pressure through said-see ond passage, an auxiliary reservoir charging communication inr part -form'edin said -casing and pipebracket, a control reservoir charging communication in part formed in said casingand pipe-bracket, said chargingvalve devicei being operative tor-assume one positionvvhen said control'chamber. isivented for causing said valve means to openisaidifirstrpassagexto said-auxiliary reservoir chargingtconrn'iunicationiand concurrently: open said ssefcond pass age :to -.said izcontrol reservoir: charging mommanication.iandresponsiveto' pressure .of fluid in. said control'chamberetoassume another position forecausing said valvexmeans' to: closet-said :firstsand zsecond passages 'to said ":auxiliary'r'reservoir ;chargingrcommunication and conu'ol'reservoir: chargingicommunication, t respectively.

:kReferences Cited-in the file of this patent V 'U-NITED STATES PATENTS V i 1,936,966 .Kasant'zefi Nov 28,' 1933 2,661,248 Keller Dec' 1, 1953 FOREIGN PATENTS 668,122 Great-Britain Mar. 12, 1952 

